Introduction: Parkinson's disease (PD) is a progressive neurodegenerative disorder that includes motor and nonmotor symptoms. Sleep disturbance is known to decrease the quality of life in patients with PD, and there are limitations to the pharmacotherapy currently in use. Therefore, complementary treatment therapies are required to address these limitations. The traditional herbal medicines Yokukansan (YKS) and Yokukansankachimpihange (YKSCH) have been used to treat insomnia and night crying in children, suggesting their effectiveness against sleep disturbance in patients with PD. We will evaluate whether YKSCH improves sleep disturbance in PD and will identify YKS-related changes in hemodynamic parameters, and neurotransmitter and hormone levels in patients with PD experiencing sleep disturbance.
Methods: We will conduct a randomized, double-blinded, placebo-controlled parallel trial in 34 patients with PD and sleep disturbance, randomly allocating the patients to either placebo-control (n = 17) or treatment groups (n = 17). The total study period will be 16 weeks; administration of YKSCH or placebo, as intervention, will be performed for a 12-week period, and follow-up will be performed over a 4-week period. All subjects will undergo conventional treatment, and be required to maintain a regular medication schedule throughout the study period. The primary outcome measure will be the Scales for Outcomes in PD-Sleep Scale score, and the secondary outcome measures will be polysomnography results, findings from instruments related to sleep disorders, neurotransmitter and hormone levels, and hemodynamic changes in the brain cortex.
Discussion and conclusions: This trial will evaluate the effectiveness and safety of YKSCH for sleep improvement in PD with sleep disturbance, and investigate the underlying mechanism of action. We expect improvement in the scores for subjective and objective sleep scales, hemodynamic changes in prefrontal cortical activity, and changes in neurotransmitter and hormone levels. The findings will provide insight into the mechanism underlying the therapeutic effect of YKSCH in PD, and lay the foundation for further studies on whether YKSCH improves sleep disturbance in PD.
Trial registration number: Clinical Research Information Service (KCT0002869).